A capacitive coupling structure and filter

Abstract

The present invention relates to the technical field of communication equipment components, specifically to a capacitive coupling structure and a filter, a capacitive coupling structure, comprising an intermediate portion connected to a plurality of adjacent and unconnected resonators, the intermediate portion comprising a connection block for connecting the resonators, and an isolation cavity for isolating the resonators, the electric field directions of the two resonators connected to the same intermediate portion being different. A filter, comprising a plurality of resonators, at least one of the above-mentioned capacitive coupling structures being used between the plurality of resonators, the capacitive coupling structure causing capacitive negative coupling to be generated between the resonators connected thereto. The capacitive coupling structure and filter using the present solution can solve the technical problem in the prior art of using a deep-loaded frequency debugging blind hole to achieve capacitive negative coupling leading to the generation of resonance poles, achieve capacitive negative coupling through a capacitive coupling structure, eliminate low-frequency resonance poles, and avoid excessive out-of-band suppression amplitude.

Description

Technical Field

[0001] The present invention relates to the technical field of communication equipment components, in particular to a capacitive coupling structure and a filter. Background Art

[0002] With the continuous development of wireless base station communication technology, new requirements are put forward for the comprehensive performance and volume of filters, and dielectric waveguide filters have fully demonstrated their advantages in comprehensive performance and volume. With the development of multi-frequency systems, the requirements for the frequency selection characteristics and out-of-band suppression characteristics of filters are becoming higher and higher, and the introduction of capacitive coupling is one of the methods to improve the frequency selection characteristics and out-of-band suppression characteristics of filters.

[0003] At present, the way to achieve capacitive negative coupling in dielectric waveguide filters is usually to set a deep blind hole negative coupling structure, and load the coupling frequency through the deep blind hole negative coupling structure to achieve capacitive negative coupling. For example, an existing dielectric waveguide filter, its dielectric body includes two resonators, and its dielectric body is provided with a capacitive negative coupling hole in the middle of the two resonators, and the depth of the capacitive negative coupling hole is at least greater than half of the thickness of the dielectric body. By compressing the electric field of the two resonators, changing their transmission path, and being very close to the bottom surface of the resonator, a capacitive effect negative coupling is formed. However, the essence of the above-mentioned dielectric waveguide filter is to set a deep loaded frequency debugging blind hole, which will inevitably produce a resonant pole at the low end of the passband of the dielectric waveguide filter. Under the premise that the zero point position of the dielectric waveguide filter is determined, the position of the resonant pole cannot generally be adjusted at will, resulting in an excessively high out-of-band suppression amplitude, which is difficult to meet the high suppression requirements of wireless communication systems. Summary of the invention

[0004] The present invention aims to provide a capacitive coupling structure and a filter to solve the technical problem in the prior art that a resonant pole is generated by using a deep-loaded frequency adjustment blind hole to achieve capacitive negative coupling.

[0005] One of the basic solutions provided by the present invention is: a capacitive coupling structure, including an intermediate part connected to a plurality of adjacent and unconnected resonators, the intermediate part including a connecting block for connecting the resonators, and an isolation cavity for isolating the resonators, and the electric field directions of two resonators connected to the same intermediate part are different.

[0006] The beneficial effects of the basic scheme are: the setting of the middle part realizes the connection and coupling of the two resonators and constructs the transmission path. The setting of the isolation part separates the strong electromagnetic fields of the two resonators, leaving only the parts with weak electromagnetic fields to connect with each other; due to the strong electromagnetic field in the middle and the weak electromagnetic field at the edge, such an integrated structure makes the coupling between the resonators very weak, greatly reducing the coupling bandwidth. The two resonators are connected through the middle part, and the electric field direction of the two resonators connected to the same middle part is different. Due to the difference in the direction of the electric field, capacitive cross-coupling is formed through the conversion between different resonant modes, thereby changing the polarity of the filter transmission path. This scheme realizes capacitive negative coupling through a capacitive coupling structure, without the need to set a deeply loaded frequency debugging blind hole, thereby avoiding the problem of resonance poles at the low end of the passband due to the use of deeply loaded frequency debugging blind holes to achieve capacitive negative coupling.

[0007] Furthermore, the connection block includes a coupling window connected to the resonator and an isolation side connected to the isolation cavity, and the isolation side is covered with a conductive shielding layer. Beneficial effect: The setting of the conductive shielding layer can shield the interference of external electromagnetic energy, and realize the coupling of the resonator and the middle block through the coupling window, thereby eliminating the crosstalk between the resonators and improving the suppression capability of remote harmonics.

[0008] Furthermore, the connecting block is a component made of microwave dielectric material. Beneficial effects: the microwave dielectric material has a small volume, low microwave loss, a small frequency temperature coefficient, and a high dielectric constant.

[0009] Furthermore, the conductive shielding layer is a metal conductive shielding layer. Beneficial effect: Compared with conventional conductive shielding layers, the metal conductive shielding layer has a better electromagnetic shielding effect.

[0010] The second basic solution provided by the present invention is: a filter including a plurality of resonators, wherein at least one capacitive coupling structure is used between the plurality of resonators.

[0011] The basic scheme has the following beneficial effects: the capacitive coupling structure is used to realize capacitive negative coupling, and there is no need to set up a deep-loaded frequency debugging blind hole, thereby eliminating the low-frequency resonance pole generated by using a deep-loaded frequency debugging blind hole to realize capacitive negative coupling. At the same time, the structure is simple, and the setting of the capacitive coupling structure is convenient for installation and debugging.

[0012] Furthermore, the capacitive coupling structure generates capacitive negative coupling between the resonators connected thereto. Beneficial effect: The capacitive coupling structure eliminates the low-frequency resonance pole, avoids excessive out-of-band suppression amplitude, and thus meets the high suppression requirements of the wireless communication system.

[0013] Furthermore, it also includes an input electrode structure and an output electrode structure, which are respectively arranged on the two resonators. Beneficial effect: the input electrode structure is arranged as an input harmonic providing port, and the output electrode structure is an output harmonic providing port.

[0014] Furthermore, it also includes at least two debugging blind holes for adjusting the resonant frequency of the resonator, and the debugging blind holes are respectively located on different resonators. Beneficial effect: By adjusting the depth and size of the debugging blind holes, the resonant frequency of the resonator corresponding to the debugging blind holes can be adjusted.

[0015] Furthermore, the plurality of filters are all covered with a conductive shielding layer. Beneficial effect: The provision of the conductive shielding layer can shield interference from external electromagnetic energy.

[0016] Furthermore, the conductive shielding layer is a metal conductive shielding layer. Beneficial effect: Compared with conventional conductive shielding layers, the metal conductive shielding layer has a better electromagnetic shielding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a capacitive coupling structure embodiment 1 of the present invention;

[0018] Figure 2 A curve diagram showing the variation of the coupling degree with the coupling window width in a first embodiment of a capacitive coupling structure of the present invention;

[0019] Figure 3 This is a schematic diagram of the structure of a filter embodiment 2 of the present invention;

[0020] Figure 4 A bottom view of a filter embodiment 2 of the present invention;

[0021] Figure 5 This is a schematic structural diagram of a frequency debugging blind hole using deep loading in a filter embodiment 2 of the present invention;

[0022] Figure 6 A filter of the present invention Figure 4 Frequency response curve of the filter in the figure;

[0023] Figure 7 A filter of the present invention Figure 2 Frequency response curve of the filter in Figure 2. DETAILED DESCRIPTION

[0024] The following is further described in detail through specific implementation methods:

[0025] Embodiment 1

[0026] Reference numerals in the drawings of the specification include: a first resonator 101 , a second resonator 102 , a connecting block 103 , and a first debugging blind hole 104 .

[0027] A capacitive coupling structure, such as the attached Figure 1 As shown, it includes a middle part connected to multiple adjacent and unconnected resonators. In this embodiment, the number of resonators is two and the number of corresponding middle parts is one. For the convenience of distinction, the two resonators are respectively defined as a first resonator 101 and a second resonator 102.

[0028] The middle part includes a connection block 103 for connecting the resonators and an isolation cavity for isolating the resonators. The electric field directions of the two resonators connected to the same middle part are different. In this embodiment, the first resonator 101 is arranged in a horizontal direction, and the second resonator 102 is arranged in a vertical direction, that is, the connection block 103 is respectively connected to one end of the first resonator 101 and one side of the second resonator 102. The connection block 103 is a component made of microwave dielectric material. In this embodiment, the middle part is made of ceramic material, and the resonators are also made of ceramic material.

[0029] The connection block 103 includes a coupling window connected to the two resonators and an isolation side connected to the isolation cavity, the isolation side is covered with a conductive shielding layer, the conductive shielding layer is a metal conductive shielding layer, and in this embodiment, the conductive shielding layer is made of silver. The shape of the coupling window can be rectangular, square, circular, etc. In this embodiment, the shape of the coupling window is square. Similarly, the shape of the side of the connection block 103 where the coupling window is located can be rectangular, square, or circular. In this embodiment, the shape of the side of the connection block 103 where the coupling window is located is square, that is, the entire side of the connection block 103 where the coupling window is located is the coupling window.

[0030] A first debugging blind hole 104 is provided on the first resonator 101 along the electric field direction, and the resonant frequency of the first resonator 101 is adjusted by adjusting the depth, size or shape of the first debugging blind hole 104. The two resonators are connected through a capacitive coupling structure, and because the electric field directions of the two resonators are different, capacitive cross coupling is formed through the conversion between different resonant modes, thereby changing the polarity of the filter transmission path, eliminating the low-frequency resonance pole, and avoiding excessive out-of-band suppression amplitude.

[0031] When in use, the width and height of the coupling window of the connection block 103 can be adjusted according to filters with different bandwidth requirements, thereby adjusting the coupling degree of the capacitive coupling structure to meet different requirements. For example, in this embodiment, the thickness of the connection block 103 is 1.5 mm. When the height of the coupling window is fixed, the magnitude of the coupling degree varies with the width of the coupling window. The variation curve is as follows: Figure 2 shown.

[0032] Embodiment 2

[0033] A filter, such as the Figure 3 , Figure 4 As shown, it includes a plurality of resonators, and at least one capacitive coupling structure 206 described in the first embodiment is used between the plurality of resonators. In this embodiment, the number of resonators is five, of which four resonators are arranged in the horizontal direction, and the remaining one resonator is arranged in the vertical direction. For the convenience of distinction, the resonators arranged in the vertical direction are defined as the first resonator 201, and the resonators arranged in the horizontal direction are defined as the second to fifth resonators, respectively. In this embodiment, the number of the capacitive coupling structures 206 used is two, which are respectively arranged on both sides of the first resonator 201, and are used to connect with the third resonator 203 and the fourth resonator 204. The two capacitive coupling structures 206 respectively generate capacitive negative coupling between the first resonator 201 and the third resonator 203, and generate capacitive negative coupling between the first resonator 201 and the fourth resonator 204.

[0034] Attach Figure 2 The upper, lower, left, right, front and rear are defined. The middle of the front side of the second resonator 202 is connected with a common coupling structure, and the front side of the common coupling structure is connected to the right end of the rear side of the third resonator 203. The fourth resonator 204 and the fifth resonator 205 are connected in the same way as the second resonator 202 and the third resonator 203, and are symmetrically arranged on the right side of the second resonator 202 and the third resonator 203. The rear end of the right side of the second resonator 202 is connected to the rear end of the left side of the fifth resonator 205 through another common coupling structure. The middle of the right side of the third resonator 203 is connected to a capacitive coupling structure 206, and the right side of the capacitive coupling structure 206 is connected to the middle of the lower left side of the first resonator 201, which is symmetrically arranged. The middle of the left side of the fourth resonator 204 is connected to another capacitive coupling structure 206, and the left side of the capacitive coupling structure 206 is connected to the middle of the lower right side of the first resonator 201.

[0035] During specific production, it is only necessary to control the position and structural dimensions of the second to fifth resonators and the common coupling structure through a mold used for ceramic sintering, and integrally mold the second to fifth resonators and the common coupling structure. After fine-tuning the dimensions and surface treatment, a conductive material layer is attached to the surface, such as a silver layer, that is, the surface is plated with metallic silver, and a coupling window originally designed for coupling with the capacitive coupling structure 206 is opened on the conductive material layer. Finally, it can be coupled and assembled with the capacitive coupling structure 206 which is also attached with a conductive material layer and has a coupling window.

[0036] A debugging blind hole 207 for adjusting the resonant frequency of the resonator is provided at the center of the top of the second to fifth resonators. The axial direction of the debugging blind hole 207 is the electric field direction of the resonator, and the number of the debugging blind hole 207 on the same resonator is one. The resonant frequency of the resonator where the debugging blind hole 207 is located is adjusted by adjusting the depth, size or shape of the debugging blind hole 207. An input electrode structure 208 and an output electrode structure 209 are provided at the center of the bottom of the second resonator 202 and the fifth resonator 205, respectively. The input electrode structure 208 and the output electrode structure 209 each include a coupling hole and a coupling ring, and the outer wall of the coupling ring is connected to the inner wall of the coupling hole.

[0037] The filter is covered with a conductive shielding layer, including the surface of the filter, the surface of the debugging blind hole 207, the surface of the input electrode structure 208 and the surface of the output electrode structure 209. The conductive shielding layer is a metal conductive shielding layer. In this embodiment, the material of the conductive shielding layer is silver.

[0038] The structural diagram of the filter using the deep-loaded frequency debugging blind hole 207 in the prior art to achieve capacitive negative coupling is shown as follows: Figure 5 As shown in the frequency response curve, Figure 6 shown. Figure 6 The horizontal axis is the operating frequency in megahertz (MHz), and the vertical axis is the corresponding frequency of the dielectric waveguide filter in dB.

[0039] The frequency response curve of the filter in this embodiment is as follows: Figure 7 shown. Figure 7 The horizontal axis is the operating frequency in gigahertz (GHz), and the vertical axis is the corresponding frequency of the dielectric waveguide filter in dB.

[0040] From the attached Figure 6 and attached Figure 7 It can be seen that in the prior art, a resonance pole is generated at the low end of the passband (2250MHz), resulting in an excessively high out-of-band suppression amplitude, which is difficult to meet the high suppression requirements of the wireless communication system. However, the present solution introduces a transmission zero at the low end of the passband 3450-3550MHz, which verifies the feasibility of a capacitive coupling structure 206 provided by the present invention. At the same time, no parasitic capacitive negative coupling resonance pole is generated at the low end of the passband, thereby solving the deficiencies in the prior art.

[0041] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can know all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A capacitive coupling structure, characterized in that: The invention comprises a middle part connected to a plurality of adjacent and unconnected resonators, the middle part comprising a connection block for connecting the resonators, and an isolation cavity for isolating the resonators, and the electric field directions of two resonators connected to the same middle part are different; The connection block includes a coupling window connected to the resonator, and an isolation side connected to the isolation cavity, wherein the isolation side is covered with a conductive shielding layer; A first debugging blind hole is opened on the first resonator along the electric field direction, and the resonant frequency of the first resonator is adjusted by adjusting the depth, size or shape of the first debugging blind hole; The two resonators are connected through a capacitive coupling structure. Since the electric field directions of the two resonators are different, capacitive cross coupling is formed through the conversion between different resonance modes. When in use, the width and height of the coupling window of the connection block are adjusted according to filters with different bandwidth requirements, thereby adjusting the coupling degree of the capacitive coupling structure to meet different requirements.

2. A capacitive coupling structure according to claim 1, characterized in that: The connecting block is a component made of microwave dielectric material.

3. A capacitive coupling structure according to claim 1, characterized in that: The conductive shielding layer is a metal conductive shielding layer.

4. A filter comprising a plurality of resonators, characterized in that: At least one capacitive coupling structure as claimed in any one of claims 1 to 3 is used between multiple resonators.

5. A filter according to claim 4, characterized in that: The capacitive coupling structure generates capacitive negative coupling between the resonators connected thereto.

6. A filter according to claim 4, characterized in that: It also includes an input electrode structure and an output electrode structure, and the input electrode structure and the output electrode structure are respectively arranged on the two resonators.

7. A filter according to claim 4, characterized in that: It also includes at least two debugging blind holes for adjusting the resonant frequency of the resonator, and the debugging blind holes are respectively located on different resonators.

8. A filter according to claim 4, characterized in that: A conductive shielding layer is provided over the plurality of filters.

9. A filter according to claim 4, characterized in that: The conductive shielding layer is a metal conductive shielding layer.

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